Staurosporin

The cyclized products 393 can be prepared by the intramolecular coupling of diphenyl ether or diphenylamine(333,334]. The reaction has been applied to the synthesis of an alkaloid 394[335]. The intramolecular coupling of benzoyl-A-methylindole affords 5-methyl-5,10-dihydroindenol[l,2-b]indol-10-one (395) in 60% yield in AcOH[336]. Staurosporine aglycone (396) was prepared by the intramolecular coupling of an indole ring[337]. 

The interest in indolocarbazoles began in the early 1950s with the first rational synthetic approaches. Since then, this interest has escalated dramatically as numerous derivatives of indolo[2,3-a]carbazole (1) have been isolated from various natural sources. These derivatives were demonstrated to possess highly potent and diverse biological effects, prompting novel efforts in the area. In particular, derivatives of indolo[2,3-n]pyrrolo[3,4-c]carbazole, such as the alkaloid staurosporine (8), have attracted much attention. 

The Michael addition of the carbanions derived from esters to nitroalkenes followed by reductive cycLizadon has been used extensively for the preparation of pyrrondin-3-ones fEq 1076 This strategy is used for synthesis of the carbaaole alkaloid staurosporine aglycon CK-352c ... 

S, S) -bis (1 -phenyl) ethylamide 154 stachyflin 306 staurosporine 300 steric bulk 178... 

Apoptotic initiator caspases (caspase-2, -8, -9 and -10) constitute a subgroup of the caspase family. These caspases are the first to become proteolytically active in the apoptotic cascade. Their activation takes place in multiprotein complexes initiated by pro-apoptotic stimuli, such as TNFa, a-Fas, staurosporine. Once activated, they can process their substrates, which include the apoptotic executioner caspases. 

In contrast, UCN-01, a staurosporine derivative, acts as a potent inhibitor of the Chkl kinase and efficiently abrogates the G2 checkpoint upon DNA damage. Die forced entry into mitosis in the presence of DNA damage results in a mitotic form of apoptosis. Several clinical trials are currently exploring a combined treatment with UCN-01 and various DNA damaging diugs. In the same vein, inhibitors of Chk2 are developed and tested in clinical trials. 

Staurosporine, a kinase inhibitor, also suppressed PAL transcription and enzymatic activation, which indicates that the phosphorylation of still unknown (transcription) factors happened in response to stimulation by pectic fragments. However, another staurosporine-insensitive but salicylic acid responding pathway led to the transcription of pathogenesis related (PR) genes [26]. 

Fig. 12. Tentative model of the signal transduction chain that links the perception of pectic fragments to defense responses in carrot cells. Abbreviations apy, heterotrimeric G protein CaM, calmodulin 4CL, 4-coumarate-CoA ligase CTX, cholera toxin FC, fusicoccine GDP-P-S and GTP-y-S, guanosine 5 -0-(2-thiodiphosphate) and guanosine 5 -0-(3-thiotriphosphate) IP3, 1,4,5-inositol trisphosphate PAL, phenylalanine ammonia-lyase PLC, phospholipase C PR, pathogenesis related PTX, pertussis toxin Rc, receptor SP, staurosporine. Activation and inhibition are symbolized by + and -respectively.

Ping L, Kimihiro M, Tohru Y, Yasushi O. Nardosinone, the first enhancer of neurite outgrowth-promoting activity of staurosporine and dibutyryl cyclic AMP in PCI 2D cells. Dev Brain Res 2003 145 177-183. 

Figure 6.14. Kinetics of 02 secretion by activated neutrophils. Neutrophil suspensions (5 x 10s/ml) were suspended in RPMI 1640 medium containing 75 /JM cytochrome c. In (b) and (d), suspensions contained 100 nM staurosporine. At time zero, suspensions in (a) and (b) were stimulated by the addition of 1 /iM fMet-Leu-Phe, whilst suspensions in (c) and (d) were stimulated by the addition of 0.1 fi g/ml PM A. Reference cuvettes were identical to the sample cuvettes, but additionally contained 30 jUg/ml SOD. The bar marker represents a A4 of 0.03 in (a) and (b), or 0.08 in (c) and (d). Similar results were obtained using the more specific protein kinase C inhibitor, bisindolylmaleimide.

It is known that protein kinase C can phosphorylate a number of key oxidase components, such as the two cytochrome b subunits and the 47-kDa cytoplasmic factor. This process is prevented by protein kinase C inhibitors such as staurosporine (although it is now recognised that this inhibitor is not specific for protein kinase C), which also inhibits the respiratory burst activated by agonists such as PMA. However, when cells are stimulated by fMet-Leu-Phe, translocation of pAl-phox to the plasma membrane can occur even if protein kinase C activity is blocked - that is, phosphorylation is not essential for the translocation of this component in response to stimulation by this agonist. Similarly, the kinetics of phosphorylation of the cytochrome subunits do not follow the kinetics of oxidase activation, and protein kinase C inhibitors have no effect on oxidase activity elicited by some agonists -for example, on the initiation of the respiratory burst elicited by agonists such as fMet-Leu-Phe (Fig. 6.14). Furthermore, the kinetics of DAG accumulation do not always follow those of oxidase activity. Hence, whilst protein kinase C is undoubtedly involved in oxidase activation by some agonists, oxidase function is not totally dependent upon the activity of this kinase. 

Figure 6.15. Structures of some protein kinase C inhibitors. Staurosporine is a potent inhibitor of protein kinase C, but is not selective. Some derivatives of protein kinase C, such as Ro31-8220 and Ro31-8425, retain a potency similar to that of the parent molecule in protein kinase C inhibition, but are much more specific.

S6, and SlOb) and two 20S a-subunits (C8 and C9) are known to be phosphoryl-ated. Phosphorylation appears to be particularly important for 26S proteasome assembly and stability. The kinase inhibitor staurosporine reduces 26S proteasome levels in mouse lymphoma cells [135] and interferon y results in reduced phosphorylation of 20S proteasome a-subunits and decreased 26S proteasome levels [141]. 

Digitoxin Staurosporine General kinase inhibitor uptake via caveolae (and via clathrin ) Described to discriminate 53 ... 

Staurosporine (2-5 pM, 60 minutes), a general kinase inhibitor, has been used to discriminate caveolae-mediated uptake from clathrin-mediated uptake (63). 

Alves da Costa, C., Mattson, M.P., Ancolio, K., Checler, F. (2003) The C-terminal fragment of presenihn 2 triggers p53-mediated staurosporine-induced apoptosis, a function independent of the presenilinase-derived N-terminal counterpart. J. Biol. Chem., 278,12064-12069. 

Fig. 2.5 Concentrations of staurosporine in eluate fractions obtained in sequential CPC spin column/HPLC ESI-MS experiments. Mixtures of compounds were spiked with staurosporine and incubated with PKA (-A-) and without PKA (-o-) as a control. The first eluate fraction shows the most significant ligand concentration difference between the protein-ligand and control samples. Reprinted from reference [16] with permission from Elsevier Science.

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